/Engine/Source/Runtime/MovieScene/Public/Evaluation/PreAnimatedState/MovieScenePreAnimatedStateStorage.h
Check whether a piece of cached storage has been initialized yet. This will be false where multiple entities contribute to an object's state but a different entity actually assigns the value (eg multiple blended entiies). Saving state for these requires 2 passes: firstly we gather all the entities that contribute to the state (which may not be able to even knowhowto cache the state), then we capture the actual value.
bool IsStorageInitialized ( [FPreAnimatedStorageIndex](API\Runtime\MovieScene\Evaluation\PreAnimatedState\FPreAnimatedStorageIndex) StorageIndex ) const